1. Field of the Invention
The present invention relates to a waste toner collecting apparatus and an image forming apparatus, and more particularly to a transporting mechanism that transports waste toner in a toner collecting chamber.
2. Description of the Related Art
Among image forming apparatuses are laser printers, facsimile machines, copiers, and the like that use an electrophotographic image forming process. An electrophotographic image forming process employs toner to develop an electrostatic latent image into a visible image or a toner image. After the toner image is transferred onto a print medium, some toner remains on the surface of a photoconductive drum. This residual toner is removed from the photoconductive drum and is collected into a toner collecting chamber provided within the electrophotographic image forming apparatus. One way of collecting waste toner is to allow the residual toner to fall by gravity into a toner collecting chamber. However, this way of collecting waste toner requires a toner chamber to extend vertically so that the toner chamber has a sufficient volume to accommodate the residual toner. This often places some limitations on efficient utilization of space in the image forming apparatus. Another way of collecting the waste toner is to transport the collected residual toner in a horizontal toner chamber. This requires a waste toner transporting mechanism (e.g., a spiral) in the horizontal chamber.
However, if the waste toner transporting mechanism has the ability to transport the toner across its length in the toner chamber, the waste toner tends to pile up at a downstream space with respect to the direction of travel of the waste toner while an upstream space is still capable of holding the waste toner. Thus, the waste toner at the downstream space is over packed to exert an extremely large load on the waste toner transporting mechanism, failing to hold any more waste toner in the chamber.
Likewise, if the waste toner transporting mechanism has the ability to transport the toner only part of its length along the toner chamber, the waste toner will not reach the downstream space, so that the downstream space is not effectively used to hold the waste toner.